PC causes router to stop working

I am in a new apartment, so I got a new Internet connection which worked fine for a month or two. However, it has started to fail every couple of days, or even once a day. After a long time of trying to figure out he problem on my own, I noticed that once the Internet fails, I can unplug the Ethernet cable connecting my pc and my router and the wireless Internet works just fine. The moment I reconnect my computer, it fails again. The ony other clue I have is that the speedtest app on my iTouch shows that uploading works just fine even when the connection is broken.

Oh, I forgot tomention that heconly way to temporarily fix the problem is to return my router to factory settings and redo the whole installation process. Needless to say, it is becoming a hastle to do that do often